Foils for Cruising and/or Cruiser/Racer Trimarans?

Discussion in 'Multihulls' started by Doug Lord, Feb 26, 2019.

  1. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Seems to me that at least part of the new foil system being used on Maserati and all the ULTIMS might have some benefits on cruiser or cruiser racer trimarans. I'd like to hear what others think- particularly, those who sail or have sailed such boats. I'm not necessarily talking about "add-on" foils but design from scratch including them.
    ---
    For reference , I'm talking about a lifting foil( controllable AOI or flap on lifting foil-capable of downforce) on a daggerboard coupled with a rudder T-foil (with adjustable AOI/flap) on the main hull.
    And possibly the use of uptip foils on the amas? Basically, uptip foils might only be suitable if it was desired that the boat fly. Foil assist solutions would probably work better on amas for a "cruiser"(curved foils?) and/or no foils with a planing hull(as described by G.Verdier).
    The idea, as a first priority, would be to use the foils to improve sea keeping ability/handling, and, second to increase speed a bit-foil assist not necessarily full flying.
    Any comments would be appreciated........
     
    Last edited: Feb 27, 2019
  2. Doug Lord
    Joined: May 2009
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    Location: Melbourne, Florida

    Doug Lord Flight Ready

    Banque Pop render w-mainfoil.png
     
  3. Corley
    Joined: Oct 2009
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    Corley epoxy coated

    Get away from a few high profile projects and race boats and the technology level most people aspire to is modest. Why? Well there is enough stuff that breaks already without adding more to the mix.

    I always chuckle about the cruiser/racer designation it's like the two are not basically diametrically opposed. A racer wants the lightest boat with the minimum of equipment on board a cruiser wants a nice galley/pantry/fridge and comfortable berths, adequate anchoring gear a decent amount of payload for cruising stuff. Sailing performance is in the mix but a rather low priority.

    The number one deal breaker for me would be how can you pull up and remove the daggerboard with a T foil on the bottom? I'm guessing there is no practical way of making the T section of the daggerboard easily removable? Drying the boat out on a sandbank would seem to be out and most amateur race programs would want to be able to do that. A swinging or cassette style T rudder isn't so bad even if it's more complex than an ordinary rudder it's accessible and easily removable for maintenance.
     
  4. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Might be able to use a pivoting "L" shaped "leeboard" on one or both sides of the main hull. This basic foil system would improve handling while adding to the comfort at sea and when anchored.
     
  5. Corley
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    Corley epoxy coated

    It would require some pretty major engineering as I see it as the pivot loads would be very high. The asymmetry wouldn't matter too much though. Has a leeboard been tried on a large trimaran before? I know some of the small trimarans like the designs from Frank Smoot use them.
     
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  6. Doug Lord
    Joined: May 2009
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    Location: Melbourne, Florida

    Doug Lord Flight Ready

    I've been thinking that a lot of "cruising" cats use fixed keels-they must have to clean them on a regular basis? Maybe that would work on the main t-foil as well?
    I don't know of any leeboard arrangement on a tri main hull but I'm reasonably sure it could work-I'm not sure it's better than just cleaning the T-foil. For inspection or work the t-foil could be dropped out and hauled on deck?
     
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